Timing light



Oct. l0, 1961 J. A. UMBARGER 3,004,191

TIMING LIGHT Filed Dec. 18, 1959 indicator.

3,004,191 TMlNG LIGHT James A. Umbarger, Cheboygan, Mich., assigner to Fox Valley Instrument Company, inc., Cheboygan, Mich., a corporation of Michigan Filed Dec. 18, 19559, Ser. No. 860,400 7 Claims. (El. 315-419) This invention relates to ignition timing devices, and more particularly toV a timing light device and a power supply therefor which is operable from either one'of two voltage sources.

A main object of the invention is to provide a novel and improved timing light device for timing an automobile engine or similar device having an ignitonjsystem, the timing light being simple in construction, being reliable in operation and employing relatively light, compact and inexpensive parts.

A further object of the invention is to provide a device of the vibrator type for the conversion of one direct current voltage to another direct current voltage, wherein the supply voltage may be either one of two different values, the device being especially useful when employed in conjunction with a timing light or other similar apparatus.

A still further object of the invention is to provide an improved dual voltage timing light device for correlating the point of ignition in a cylinder'of an internal combustion engine with the rotation of an element, such as a ily wheel, driven by the engine, the device being adapted for use with either one of two different input voltages and being provided with manual selecting means to set the device in accordance with the supply voltage, the device being further provided with means to automatically check the setting of the manual selecting switch and to allow the device to be energized only when the manual voltage-selecting switch has been set to its proper position.

Further objects and advantages of the invention will become -apparent from the4 following'V description and claims, and from the accompanying drawing, wherein the single figure illustrates the electrical circuit of an improved timing light and a power supply therefor constructed in accordance with the present invention,

Timing light systems of the prior art utilize a voltage sensitive relay to select appropriate transformerprimary windings of a high voltage transformer employed to provide the necessary high voltage to energize a .gas discharge tube which is employed as the visual timing In the prior art devices, the supply current is directed through the contacts of the voltage sensitive relay, the contact selected depending upon the supply voltage. This arrangement is frequently subject to failure because of the burning of the relay contacts by the supply current. To overcome this, more powerful relays have been employed, which necessitates larger'and more costly apparatus. A timing light of the nature-.contemplated by the present invention is ordinarily a hand-held device, and therefore it is necessary to keep its bulk to a minimum in order to employ the device conveniently. Therefore, it is desirable to avoid the use of the higher powered, heavier relays above mentioned, if the necessary reliability can be more simply achieved.

The device of the present invention substantially improves the reliability of a dual voltage timing light system by utilizing a simple manually operated voltage selector switch to carry the` supply current to whichever transformer primary winding is appropriate for'the supvply voltage being used, while at the same time making it Vimpossible t apply power to the timing light unless 4,the switch is positioned appropriately for the voltage to which the timing light device is connected; This result 3,04,191 ratented oct. io, 19er is achieved by providing a series circuit through the vibrator driving coil, through the contacts of a small voltage-sensitive relay, and through extra contacts provided on the manually operated voltage-selecting switch, so that the driving coil of the vibrator, the contacts of the relay, and the contacts of said manually operated switch will complete a circuit through the driving coil of the vibrator only when the voltage-sensitive relay is in agreement with the voltage selecting switch position. While the present invention has been embodied by way of example in connection with a timing light apparatus, the broad concept thereof is similarly applicable to all types of vibrator power supplies wherein one direct current voltage is converted into a different direct current voltage, and wherein the supply voltage may be either one of two different values. Referring to the drawing, 11 generally designates a timing light circuit constructed in accordance with the present invention. The circuit 11 comprises a pair of input terminals 12 and 13 adapted to be connected to a source of D.C. voltage, which may be either of two different voltages. For example, the voltage source may be either six volts or twelve volts, as in the case of the present conventional automobile electrical systems.

Designated generally at 14 is a vibratable contact device of the type having coupled vibratory armatures or reeds 15 and 16 which oscillate between respective top and bottom pairs of contact points 17, 18 and 19, 20. The device 14 is provided with a driving coil 21 having one terminal thereof connected to an upper contact point 22 which is normally engaged by the upper reed 15 of the vibrator unit but which disengages therefrom intermittently as the reed 15 oscillates. The remaining terminal of the driving coil 21 is connected by a wire 23 to the armature 24 of a voltage-sensitive relay 25. The armature 24 normally engages an upper contact 26 of the relay and remains in that position for as long as less than a predetermined voltage is applied to the relay winding. When the supply source is six volts, for example, insumcient current flows through the relay winding to attract the armature 24 and move it away from the contact 26. However, when a substantially higher voltage, for example twelve volts, is applied to the relay winding, the armature 24 is attracted and is moved downwardly into engagement with a lower contact 27. I The elements 24, 26 and 27 form part of apparatus for controlling operation of the vibrating device 14, as will appear more fully hereinafter.

Designated generally at 23 is a manually operated voltage-selecting switch of the double-pole, double-throw type, the switch comprising the upper pole 29 and the lower pole 30 mechanically coupled together. The switch includes the upper stationary contacts 31 and 32, engageable respectively by the poles 29 and 3@ when the poles are in their upper positions, as viewed in the drawing, and the lower contacts 33 and 34, engageable respectively by the poles 29 and 30 when the poles have been adjusted to their lower positions, as viewed in the drawing. The contacts 31 and 33 constitute taps for varying the number of turns of the primary winding utilized during operation of the apparatus, and the pole 29 thus may be considered a tap changing device.

' Designated atr35 is a step-up transformer having primary winding 36 and a secondary winding 37. The secondary winding 37 is connected to the respective terminals of a gaseous discharge tube 38, for example, a tube containing Zenon gas, through a suitable rectifier 39. The transformer 3S steps up the voltage supplied thereto suiciently to cause ionization of the gas in the discharge tube 3S in response to the proximity of a high voltage, such as an electrode 40 which is connected to a spark plug or similar high voltage element by a conductor 41. The output voltage from the secondary winding 37 is rectified by the rectifier 39 and the rectified.

pulses are stored in a condenser d2 connected across the terminals 43 and dit of the discharge tube 38. When the charged conductor d@ is disposed in proximity to the discharge tube 38, the tube becomes conductive and luminous because of the voltage on the electrode 4G, the discharge of the tube 33 being for only a very short duration, namely, the time required to discharge the condenser 42, ailowing the gas in tube 33 to deionize and stop the current flow. Condenser e2 recharges and the light ash repeats each time the spark plug is energized. The flashes occur at a repetitive rate, depending upon the engine speed, so that the stroboscopic effect thus obtained can be utilized to observe the instantaneous position of a moving part, such as a point on the fly wheel, of the engine under test when the spark plug is energized. A buffer condenser t5 is connected across the terminals of transformer secondary winding 37 to shunt out any undesirably high transient voltages which may develop on the windings of transformer 35. A resistor d6 is connected across the condenser 42 to further stabilize the voltage from the transformer 35.

A grounding conductor 47 is connected between the terminal i3 of transformer secondary 37 and `the armature 15 of the vibrator 14 to prevent high voltage induced from the spark plug connector wire d1 from straining the insulation of transformer 35.

The respective input terminals y12 and 13 are connected to the reeds 1.5 and 16 by wires 49 and 53u As above mentioned, the reeds 15 and 16 are mechanically coupled together, but are electrically insulated from each other, vibrating in unison.

Supply conductor i? is connected to the lower pole 3d of switch 2S by a conductor 51 and a manually controlled switch 52. Switch contact 32 is connected to the upper relay contact 26 by a wire 53. Switch contact 34 is connected to the lower relay contact 27 through a wire 5e and a current-limiting resistor 55. The contacts 24, 32 and 27, 34 thus may be considered as two separate sets of connected contacts. The winding of the relay 25 is connected across the wires 51 and 47.

The vibrator contacts 1S and 19 are connected together by a wire 56, and said wire 56 is connected by a wire S7 to the upper switch pole or tap changer 29. The upper contact 31 associated with the switch pole 29 is connected by a wire 53 to an intermediate point on the transformer primary winding 36, whereby to select the portion of the transformer primary winding appropriate for use with the lower of the two possible input voltages, for example, six volts. The lower contact 33 'associated with the switch pole 29 is connected to an end terminal of the primary winding 35. The opposite end terminal of said primary winding is connected by a wire 59 to the upper vibrator contact 17. Vibrator contact 17 is connected to the lower vibrator contact 20 by a wire 60. The parts just referred to constitute the circuit of the transformer primary winding and it is important to note that none of the apparatus for energizing the vibrator coil 21, except for terminals 12 and 13, forms any part of the transformer circuit.

With the manual switch 28 in the position shown in the drawing and with the terminals 12 and 13 connected to the lower of the two possible supply voltages, for example, six volts, when the switch 52 is closed, the driving coil 21 of the vibrator will be energized by a circuit comprising terminal 13, wire 50, wire 51, switch 52, pole 30, contact 32, wire 53, contact 26, armature 24, wire 23, the winding of the vibrator 21, the contact 22', the armature 15, the supply wire 49, and the remaining input terminal 12. This causes vibration of the armatures 15 and 16, intermittently opening and closing the energizing circuit for the vibrator driving coil 21. The selected portion of the transformer primary 36 therefore receives periodic pulsations of current. and the resultant pulsations of voltage induced in the primary cause a high induced voltage to be developed in the secondary 37 which is rectified and applied to the terminals of the discharge tube 33. When the electrode 43 is connected to a spark plug and is then placed in close proximity to the tube, the gas thereinfires, as above described, producing the rapidly recurring dashes and providing the desired stroboscopic effect.

When the supply voltage is twelve volts, with the manual switch 28 in the position shown in the drawing, the voltage sensitive relay 25 moves its armature 24 into engagement with its lower contact 27, the armature diseugaging from its upper contact 26. Under these conditions, no current can flow to energize the vibrator driving coil 21, since the position of armature 24 does not agree with the position of pole 30, and the circuit is open. However, if the manual switch 28 is operated to move its poles downwardly into respective engagement withcontacts 33 and 34, the pole 30 then completes the energizing circuit to the vibrator driving coil 21 by engaging the lowerv contact 34, so that driving coil 21 becomes energized through the current-limiting resistor 55, which is of such a value as to prevent excessive currents from being supplied. to the vibrator driving coil 21 when the higher of. the two possible input voltages is employed.

When the switch pole 29 is in its lower position, namely, in engagement with the lower contact 33 associated therewith, all of the turns of the primary winding 36 are in use, which is proper for the higher voltage source. It can therefore be seen that it is impossible to energize the timing light with the wrong voltage.

The. circuit above described accomplishes the following results:

(l) It permits the use of a voltage-sensitive relay having relatively small power-handling capacity, because the relay is not required to carry any of the current which energizesthe light, carrying only the small. amount of current required to drive the vibrating reed elements 15 and 16 ofthe vibrator device 14. This tends to avoid failures due to burned relay contacts, and allows the use of small, low-power, relatively inexpensive relays.

(2) The device insures that only the appropriate primary winding of the power transformer 35 can be used for the voltage supplied, even though the supply current is furnished to the primary winding of the power transformer through al manually controlled switch pole 29'. Thus, the manually controlled switch is available to carry the supply current to the appropriate portion of the primary winding of the power transformer, and for a given size or cost, manually controlled switches are more reliable in handling current than relay-actuated switches.

It will be noted that the supply pulses for the transformer 35 are furnished directly from the input terminals 12 and 13 through the vibrating armatures 15 and 16, the armatures 15 and 16, with their associated contact 17, 18 and 19, 20 acting as a rapidly operating pole changer, causing alternating currents derived from the supply terminals 12 and 13 to be applied to the primary windiug 36 of transformer 35. The contacts of relay 25 are not required at any time to handle the currents furnished to the primary windings of said transformer.

It` will be understood that the vibrator unit 14 is of conventional construction, and that the vibratory armatures 15 and 16 thereof are biased upwardly by spring tension so that the upper armature 1S normally engages the stationary contact 22. The magnetic pull exerted by the driving coil 21, when energized, depresses the armatures 15 and 16, and causes said armatures to engage their lower contacts 18 and 20. The depression of the upper contact 15 opens the energizing circuit for the coil 21 at the stationary contact 22, interrupting the current ow to the coil, so that the spring tension on the armaturesV 15 andy 16 causes them to return to their upper positions. The inertia of the armatures causes them to move upwardly sufliciently to engage the upper contact elements 17 and 19. The re-established circuit for the driving coil 21 causes the armatures 1S and16 to be again depressed, repeating the cycleabove described and causing steady oscillation ofthe armatures 15 and 16 at a definite frequency.

It will be readily understood that the spirit of the invention is not limited to the specilic circuit illustrated in the drawing and will apply equally in the case of the vibrator power supply circuits which do not have the separate interrupter contact 22, the only requirement being that the driving coil 21 be associated with the voltagesensitive relay contacts and the manually operated voltage selecting switch contacts in the manner illustrated in the drawing. The circuit is also applicable to use with vibrators having a single reed employed in combination with a power transformer ofthe type having a centertapped primary winding. Similarly, the circuit of the present invention is also applicable with vibrators of the self-rectifying type.

While the switch device 28 has been illustrated and described as a double-pole, double-throw manually operated switch, the present invention contemplates the use of any connection-changing device which includes respective conductors and respective contact elements selectively engageable by said conductors for changing the connections. For example, a plug or connecting strip may be employed instead of a double-pole, double-throw switch.

Furthermore, where a manually operated double-pole, double-throw switch is employed, it is preferable, although not absolutely necessary, to employ a type of switch which has an off position through which the switch must pass, the off position being located between the six volt and twelve volt positions, the switch being constructed so as to make it impossible to go through the olf position without a momentary pause in the off position. This allows the vibrating reed elements in the vibrator to come to rest before the six volttwelve volt connections are changed. Otherwise, the reed elements, due to inertia, may coast for a short interval of time, which may produce difficulty if the switch is instantly changed to the wrong connection.

While a specific embodiment of an improved timing light device has been disclosed in the foregoing description, it will be understood that various modications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. Apparatus for producing a timed signal from a selected one of a plurality of different D.C. voltage sources, said apparatus comprising input terminals adapted for connection to a selected one of said sources; transformer means including a primary winding and a secondary winding, said primary winding having a number of taps for selectively increasing and decreasing the number of turns of said primary winding to be utilized according to the voltage value of a selected one of said sources; tap changing means for connection to selected taps of said primary winding; circuit means including vibratable contacts interconnecting said terminals and said primary winding via said tap changing means for periodically completing and breaking an electrical circuit between a selected voltage source and said primary winding upon operation of said vibratable contacts so as periodically to induce voltages in said secondary winding of said transformer means; an energizing circuit interconnecting said terminals and said vibratable contacts, said energizing circuit being electrically independent of said circuit means; and means connected to said secondary winding operable to produce a signal in timed relation to the induction of voltages therein.

V2.' Apparatus as set forth in claim 1 wherein said energizing circuit includes a voltage sensitive relay having an armature movable from a normal position in circuit with said vibratable contact means to a second position out of circuit with said vibratable contact means in response to the application of a voltage having a predetermined value to said relay. v

3. Apparatus as set forth inv claim 2 including manually operable switch means for reconnecting said armature in circuit with said vibratable contact means when said armature is in said second position.

4. Apparatus as set forth in claim 3 wherein said manually operable switch means is ganged with said tap changing means for conjoint operation.

5. Apparatus for producing a timed signal from a selected one of two different D.C. voltage sources, said apparatus comprising input terminals adapted for connection to a selected one of said sources; transformer means including a primary winding and a secondary winding, said primary winding having a pair of taps for selectively increasing and decreasing the number of turns utilized of said primary winding in accordance with the voltage value of a selected one of said sources; tap changing means for connection to selected taps of said primary winding; circuit means interconnecting said terminals and said tap changing means and including vibratable contact means adapted periodically to complete an electrical circuit between said input terminals and a selected one of said pair of taps of said primary winding so as periodically to induce voltages in said secondary winding; an energizing circuit interconnecting said terminals and said vibratable contact means independently of said circuit means for actuating said vibratable contact means from a selected one of said voltage sources; control means in said energizing circuit coupled to said tap changing means for conjoint operation therewith, said control means being operable to break said energizing circuit and prevent actuation of said vibratable contact means` except when the tap of said primary winding to which said tap changing means is connected corresponds to the number of turns of said primary winding adapted to be utilized for the voltage of the selected source; and means connected to said secondary winding operable in response to the induction of voltages therein for producing a signal in timed relation to the induction of voltages in said secondary winding.

6. Apparatus for producing a timed signal from a selected one of two dierent D.C. voltage sources, said apparatus comprising input terminals adapted for connection to either of said sources; transformer means including a primary winding and a secondary winding, said primary winding having a fixed terminal and a pair of taps for selectively increasing and decreasing the number of turns of said primary winding Iutilized in accordance with the voltage value of a selected one of said sources; tap changing means for connection to either of said taps of said primary winding; circuit means interconnecting one of said input terminals to said transformer terminal and the other input terminal to said tap changing means, said circuit means including vibratable contact means adapted periodically to make and break an electrical circuit to said primary winding so as periodically to induce voltages in said secondary winding; an energizing circuit interconnecting said input terminals and said vibratable contact means independently of said circuit means for actuating said vibratable contact means from either of said sources; control means forming part of said energizing circuit and including a voltage sensitive relay device, a first set of connected contacts and a second set of connected contacts, either set of contacts being adapted for connection in circuit with said input terminals and said vibratable contact means to the exclusion of the other set of contacts, said control means also including switch means associated with each of said sets of contacts for selectively connecting either set in said energizing circuit,

feooffswlA one of said switch means being operable by said relay 'evicef according to the valne of the seteetedv voltage sonrce and the other switch means being operable manu# ally; and means connected to said secondary winding oper,u

able to produce a signal in Itimed relation to the induction 5 of voltages therein.

7; The apparatus set forth in claim 6 wherein said other of said switch means and said tap changingv means are interconnected for conjointoperatiem` References Cited in the le of this patent UNITED STATES PATENTS 

